(1) Field of the Invention
The present invention relates to an intake manifold of a multicylinder engine.
(2) Description of Related Art
Conventionally, as an intake manifold of a multicylinder engine, there is an intake manifold in which an entire Exhaust Gas Recovery gas (hereafter referred to as “EGR gas”) introduced into an intake air introducing sleeve portion is released from a side of a passage outlet of a gas introducing passage into an intake air passing through the intake air introducing sleeve portion.
In the conventional intake manifold, the EGR gas is likely to be diffused into part of the intake air passing through the intake air introducing sleeve portion and close to the passage outlet while the EGR gas is less likely to be diffused into part of the intake air far from the passage outlet, and concentration distribution of the EGR gas in the intake air is likely to become inhomogeneous. Moreover, the EGR gas is likely to be distributed into the cylinders on the side of the intake air introducing sleeve portion close to the EGR gas introducing passage while the EGR gas is less likely to be distributed into the cylinders on a side of the intake air introducing sleeve portion far from the EGR gas introducing passage due to the fact that the intake air passing through the intake air introducing sleeve portion functions as an air curtain. For this reason, distribution of the EGR gas into the respective cylinders is likely to become inhomogeneous.
For this reason, a function of reducing NOx and output performance are likely to become insufficient.